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Homework Help: Integration of cos

  1. Nov 13, 2009 #1
    Erm, I have this integration question:

    sqrt((1-cos(x))/2) with an upper limit of 2pie and lower limit of 0.

    I can't seem to do it right.

    I tried simplifying it:

    sqrt((1-cos(x))/2)
    = ((1-cos(x))/2)^(1/2)
    = 1 - (cos^-2(x))^(1/2)
    = 1 - cos^-1(x)

    Then I intgrated 1... which becomes x, but I have no idea how to do cos^-1(x), I saw the long formula for the integration of cos^something(x) but I don't think it applies here... because the answer is 4...
     
  2. jcsd
  3. Nov 13, 2009 #2
    bad.. BAD Dorumon!! =P

    sqrt(a + b) =/= a + sqrt(b)

    You should have some trigonometric substitutions in your notes/textbook that involve cosine. Take a look at them, and see if they make the integrand a little nicer.
     
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